The reason the USA has an unusual system of letting the guilty criminal walk free due to police misconduct is that there was no other punishment that worked to reign in the behavior.
In a perfect system the police would be punished, either civilly or criminally, for their wrongdoing, but a prosecutor will almost never bring a case against a cop who has brought them juicy evidence. It would be career suicide. So here we are.
It does not seem to work to reign bad cops behavior. What it somehow achieved instead is that it is impossible to punish cops unless they are super duper blatant.
In a perfect system the police would be punished, either civilly or criminally, for their wrongdoing, but a prosecutor will almost never bring a case against a cop who has brought them juicy evidence. It would be career suicide. So here we are.